Steven Levy, unsurprisingly, had the best retrospective day-of, thanks to an interview he got with Phil Schiller. First, Steven thought back to his interactions, including with Steve Jobs, on the day of the unveiling.

In terms of why there were no third-party apps:

According to Jobs, it was an issue of security. “You don’t want your phone to be an open platform,” he told me. “You don’t want it to not work because one three apps you loaded that morning screwed it up. Cingular doesn’t want to see their West Coast network go down because of some app. This thing is more like an iPod than it is a computer in that sense.”

Nobody's perfect. And yet:

“2007 is going to be a very big year for smart phone,” Steve Jobs told me ten years ago. “I see a lot of soccer moms with smart phones.”

Indeed.

With regard to Schiller, on the third-party app question:

Schiller also cast light on why the iPhone shipped as a closed system. During the gestation period of the iPhone, Apple hosted a spirited internal debate. Some advocated that the device be an open system, like the Macintosh, and others advised a more closed system, like the iPod. The argument was put on hold when the engineers realized that even if the open-system adherents won the debate, it would be impossible to implement in time for the launch. Steve Jobs shut down the discussion, Schiller recalls. “He said ‘We don’t have to keep debating this because we can’t have [an open system] right now. Maybe we’ll change our mind afterwards, or maybe we won’t, but for now there isn’t one so let’s envision this world where we solve the problem with great built-in apps and a way for developers to make web apps.”

Assuming that's true, and not some very kind altering of history, it's actually one of the better explanations I've read. Of course, most accounts chalk it up to Jobs simply being wrong about third-party apps (and a year later correcting his mistake with the launch of the App Store). But most of those accounts weren't in the room with him either...

“If it weren’t for iPod, I don’t know that there would ever be iPhone.” he says. “It introduced Apple to customers that were not typical Apple customers, so iPod went from being an accessory to Mac to becoming its own cultural momentum. During that time, Apple changed. Our marketing changed. We had silhouette ads with dancers and an iconic product with white headphones. We asked, “Well, if Apple can do this one thing different than all of its previous products, what else can Apple do?’”